Many types of display devices characterize a video signal so that they properly display the video signal. Characterization includes determining the height and width of the image conveyed by the video signal, which are also referred to as the boundaries of the image. Characterization may determine, for example, that a video signal conveys an image of 640×480 pixels, 1024×768 pixels, and so on. Characterization also includes determining the timing of the video signal. The timing of the video signal indicates how often the image conveyed by the video signal is refreshed, such as 60 hertz (Hz), 85 Hz, and so on. Characterization may additionally include other determinations, such as determining the actual voltage levels of an analog video signal, and determining an appropriate gamma adjustment or calibration, or, more generally, delinearization. Once a display device has properly characterized the video signal, it is able to optimally display the image conveyed by the video signal, including sizing the image properly, synchronizing to the video signal, and so on.
Typically a display device characterizes the video signal of a video source when the video source is first selected for display by the device, including when the device is first turned on, where the display device may have inputs corresponding to a number of different video sources. Most of the time the display device will likely properly characterize the video signal based on whatever image happens to be currently provided on the video signal. However, at times the display device will improperly characterize the video signal, because the image being currently provided on the video signal is not well suited for characterizing the signal. As a result, the display device may not optimally display the image conveyed by the video signal. The user of the device may become concerned that the device has malfunctioned, or perhaps worse, conclude that the device is of lower quality than previously thought.
For these and other reasons, there is a need for the present invention.